在OpenWrt中开启树莓派I2C功能
作者:互联网
编辑 /boot/config.txt
dtparam=i2c_arm=on
dtparam=i2c0=on
dtparam=i2c1=on
dtparam=spi=on
dtparam=i2s=on
通过opkg安装相关包
opkg install i2c-tools kmod-i2c-gpio kmod-i2c-algo-bit kmod-i2c-algo-pcf kmod-i2c-bcm2835 kmod-i2c-core kmod-i2c-gpio kmod-i2c-mux
使用i2c命令行工具测试
ls /dev/i2c*
i2cdetect -y 1
安装python支持
opkg install python3-smbus
I2C LCD示例代码
#!/usr/bin/python
import smbus
import time
import atexit
# Define some device parameters
I2C_ADDR = 0x27 # I2C device address
LCD_WIDTH = 16 # Maximum characters per line
# Define some device constants
LCD_CHR = 1 # Mode - Sending data
LCD_CMD = 0 # Mode - Sending command
LCD_LINE_1 = 0x80 # LCD RAM address for the 1st line
LCD_LINE_2 = 0xC0 # LCD RAM address for the 2nd line
LCD_LINE_3 = 0x94 # LCD RAM address for the 3rd line
LCD_LINE_4 = 0xD4 # LCD RAM address for the 4th line
LCD_BACKLIGHT = 0x08 # On
#LCD_BACKLIGHT = 0x00 # Off
ENABLE = 0b00000100 # Enable bit
# Timing constants
E_PULSE = 0.0005
E_DELAY = 0.0005
#Open I2C interface
#bus = smbus.SMBus(0) # Rev 1 Pi uses 0
bus = smbus.SMBus(1) # Rev 2 Pi uses 1
def lcd_init():
# Initialise display
lcd_byte(0x33,LCD_CMD) # 110011 Initialise
lcd_byte(0x32,LCD_CMD) # 110010 Initialise
lcd_byte(0x06,LCD_CMD) # 000110 Cursor move direction
lcd_byte(0x0C,LCD_CMD) # 001100 Display On,Cursor Off, Blink Off
lcd_byte(0x28,LCD_CMD) # 101000 Data length, number of lines, font size
lcd_byte(0x01,LCD_CMD) # 000001 Clear display
time.sleep(E_DELAY)
def lcd_byte(bits, mode):
# Send byte to data pins
# bits = the data
# mode = 1 for data
# 0 for command
bits_high = mode | (bits & 0xF0) | LCD_BACKLIGHT
bits_low = mode | ((bits<<4) & 0xF0) | LCD_BACKLIGHT
# High bits
bus.write_byte(I2C_ADDR, bits_high)
lcd_toggle_enable(bits_high)
# Low bits
bus.write_byte(I2C_ADDR, bits_low)
lcd_toggle_enable(bits_low)
def lcd_toggle_enable(bits):
# Toggle enable
time.sleep(E_DELAY)
bus.write_byte(I2C_ADDR, (bits | ENABLE))
time.sleep(E_PULSE)
bus.write_byte(I2C_ADDR,(bits & ~ENABLE))
time.sleep(E_DELAY)
def lcd_string(message,line):
# Send string to display
message = message.ljust(LCD_WIDTH," ")
lcd_byte(line, LCD_CMD)
for i in range(LCD_WIDTH):
lcd_byte(ord(message[i]),LCD_CHR)
def lcd_clear():
# Clear LCD screen
lcd_byte(0x01, LCD_CMD)
def main():
# Main program block
# Initialise display
lcd_init()
while True:
# Send some test
lcd_string("RPiSpy",LCD_LINE_1)
lcd_string("I2C LCD",LCD_LINE_2)
time.sleep(3)
# Send some more text
lcd_string("RPiSpy",LCD_LINE_1)
lcd_string("I2C LCD",LCD_LINE_2)
time.sleep(3)
if __name__ == '__main__':
try:
main()
except KeyboardInterrupt:
pass
finally:
#lcd_byte(0x01, LCD_CMD)
lcd_clear()
else:
lcd_init()
@atexit.register
def atexit_f():
lcd_clear()
标签:kmod,树莓,i2c,CMD,lcd,LCD,byte,I2C,OpenWrt 来源: https://www.cnblogs.com/5iwkt/p/16153764.html